In the case of X-ray apparatuses such as these, it is critically important that an X-ray source and an X-ray detector, in particular a digital X-ray detector, are arranged as exactly as possible relative to one another, in order to ensure the same high image quality all the time. Inter alia, the exact relative arrangement ensures uniformly centered illumination of the X-ray detector by an X-ray beam produced by the X-ray source, uniform dosage distribution of the X-ray beam on the X-ray detector, dazzle control that is symmetrical with respect to the X-ray detector, and alignment, accurately centered with respect to a focus of the X-ray source, of a scattered beam grid attached to the X-ray detector. In general, in an X-ray system, after installation at its intended location, the X-ray emitter and the X-ray detector are aligned relative to one another once such that any discrepancies in the instantaneous relative arrangement from an exact relative arrangement are within a tolerance value defined for the X-ray apparatus. This situation is referred to in the following text as the necessary relative arrangement.
Over the course of time, loss of adjustment can occur in an X-ray apparatus, leading to the discrepancy in the positioning of the X-ray emitter relative to the X-ray detector going considerably beyond the tolerance values, with the image quality deteriorating as a result of this. Furthermore, even in applications which require major tilting of the X-ray emitter and of the X-ray detector, it is possible for mechanical holders such as telescopic holders to be severely loaded by the masses of the components, such that the permissible tolerance values for the discrepancies are exceeded.
So-called “locating pins” are known for X-ray detectors, pins which are attached directly to the a-Si or a-Se plate of the X-ray detector, which can be aligned by means of matching holes incorporated in a holder for the X-ray detector so as to prevent any major discrepancy from the original position. Furthermore, X-ray apparatuses are also known in which the X-ray detector is held in its position by means of a spring mechanism.